package com.zheng.common.util;

import javax.servlet.ServletException;
import java.io.*;
import java.util.zip.ZipEntry;
import java.util.zip.ZipOutputStream;

/**
 * 压缩工具类
 * @author lvb10
 *
 */
public class ZipUtil {

	public static void zipFile(java.util.List<File> files, ZipOutputStream outputStream) throws IOException, ServletException {
		try {
			int size = files.size();
			// 压缩列表中的文件
			for (int i = 0; i < size; i++) {
				File file = (File) files.get(i);
				zipFile(file, outputStream);
			}
		} catch (IOException e) {
			throw e;
		}
	}
	public static void zipFile(File inputFile, ZipOutputStream outputstream) throws IOException, ServletException {
		try {
			if (inputFile.exists()) {
				if (inputFile.isFile()) {
					FileInputStream inStream = new FileInputStream(inputFile);
					BufferedInputStream bInStream = new BufferedInputStream(inStream);
					ZipEntry entry = new ZipEntry(inputFile.getName());
					outputstream.putNextEntry(entry);

					final int MAX_BYTE = 10 * 1024 * 1024; // 最大的流为10M
					long streamTotal = 0; // 接受流的容量
					int streamNum = 0; // 流需要分开的数量
					int leaveByte = 0; // 文件剩下的字符数
					byte[] inOutbyte; // byte数组接受文件的数据

					streamTotal = bInStream.available(); // 通过available方法取得流的最大字符数
					streamNum = (int) Math.floor(streamTotal / MAX_BYTE); // 取得流文件需要分开的数量
					leaveByte = (int) streamTotal % MAX_BYTE; // 分开文件之后,剩余的数量

					if (streamNum > 0) {
						for (int j = 0; j < streamNum; ++j) {
							inOutbyte = new byte[MAX_BYTE];
							// 读入流,保存在byte数组
							bInStream.read(inOutbyte, 0, MAX_BYTE);
							outputstream.write(inOutbyte, 0, MAX_BYTE); // 写出流
						}
					}
					// 写出剩下的流数据
					inOutbyte = new byte[leaveByte];
					bInStream.read(inOutbyte, 0, leaveByte);
					outputstream.write(inOutbyte);
					outputstream.closeEntry(); // Closes the current ZIP entry
					// and positions the stream for
					// writing the next entry
					bInStream.close(); // 关闭
					inStream.close();
				}
			} else {
				throw new ServletException("文件不存在！");
			}
		} catch (IOException e) {
			throw e;
		}
	}
}